What CPU temps are safe?

Discussion in 'Mac Pro' started by Jordan1990, May 12, 2015.

  1. Jordan1990 macrumors member

    Joined:
    Jan 17, 2015
    #1
    Ive been back and forth with the idea of upgrading the CPU's in my 2010 MP, purely due to the question do i actually need to. But anyway i love playing around and building computers so i went ahead and changed the 2.4ghz E5620's to 3.46ghz x5677's. I also upgraded the RAM from 16gb to 24gb which now runs at the full 1333 thanks to the CPU's.

    All went smoothly and it works fine, i know these CPU's draw more power than my old ones and ive decided to use SMC to up the fan speeds slightly but im not sure what 'safe' tempertures are? At idle it was showing 35 degrees C, but whats a safe temperture under load?
     
  2. iamMacPerson macrumors 68030

    iamMacPerson

    Joined:
    Jun 12, 2011
    Location:
    AZ/10.0.1.1
    #2
    35 at idle isn't bad at all. With my Mac Pros, I usually let the built in software control the fans until iStat Menus has a sensor go red, then I intervene and bump it up. Intel states that those processors shouldn't surpass 80.4 celsius (about 176 Fahrenheit). When it reaches 65-70 celsius I would intervene. Otherwise, I'd let the system control everything itself. OS X on Mac Pros is usually pretty good with fan control unlike on the iMacs and notebooks. Just when you really start performing intensive tasks I'd kick it up a notch.

    Personally, I have never dealt with that model of CPU so it might be better if someone who has chimed in. But I can speak from experience with my Mac Pros.
     
  3. Jordan1990 thread starter macrumors member

    Joined:
    Jan 17, 2015
    #3
    Thanks, to be honest id rather do that because i dont want to have to do it myself, but i never thought of using istat! Maximum temp is good to know, like you i wouldnt want to let it get any higher than 10 degrees C under the maximum, cutting it a bit close for me!

    Ive never heard the fans inside speed up on their own so i wasnt sure how good OSX was at determining when to speed them up, maybe ive just never pushed it enough! I know what you mean about macbooks and imacs, my old 27" imac was better than the radiators in my house as a heating device and my old macbook pro use to burn my lap when playing games.

    Thanks again for the info.
     
  4. iamMacPerson macrumors 68030

    iamMacPerson

    Joined:
    Jun 12, 2011
    Location:
    AZ/10.0.1.1
    #4
    No problem! Yeah OS X fan control sucks for the smaller machines. When I'm doing something intensive on my 13" Pro it has to reach 205 F (96.1 C) before the fans hit maximum. I don't want it above 180 F (82.2 C) and even that is pushing it for me.

    IMO iMacs are the worst for trapping heat inside since Apple likes to keep the fans quiet and the all in one enclosure makes it even worse.
     
  5. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #5
    My W3690 has a lower max temperature than your X5677 (T-case max 67.9C vs 80.4C). And it can run at constant 85C (CPU Tdoide temperature in iStat) for days without any problem (full load).

    For your info, my system ambient temperature is about 35C, and the CPU idle at around 45C.
     
  6. Jordan1990 thread starter macrumors member

    Joined:
    Jan 17, 2015
    #6
    Interesting, does it not worry you excedding the max temp by that much? Strange for them to state these max temps if they can handle more, although i suppose they have to cover themselves.
     
  7. h9826790 macrumors 604

    h9826790

    Joined:
    Apr 3, 2014
    Location:
    Hong Kong
    #7
    Not really that bad, the max temp they publish is the T-case max, which is unmeasurable in general. On the other hand, the T-diode is usually 10+ higher than the T-case. So, in my case, may be just few degrees above the max temp.

    I did monitor it closely for months when I was just install this "new" CPU last year. End up realise it's fully stable at that temperature, the Mac will just spin up the fan a bit to keep it at or below around 85C, there is no thermal warning in terminal or console.

    And a more interesting fact, the X5690 and W3690 has the same speed, same core count, basically the same architecture as well, but X5690's T-case max is 10C higher than W3690.

    I don't know why there is a difference, may be because the X5690 is designed to run in pair, so most likely will run hotter. Therefore they give it less buffer and publish a higher limit. But for me, obviously the W3690 won't burn when T-diode go above 67. Also, this kind of limitation usually with plenty of buffer.

    My Mac may run handbrake 24/7 for weeks. When I was not there, no air con for the Mac. And I am living in hot Asia. Not a single problem due to the heat so far. Therefore, I am very confident that your 5677 is good, far less thermal stress than my 3690 anyway.
     

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